Charales is an order of pondweeds, freshwater algae Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are in the division Charophyta The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are totally lacking. Flagellate cells in the form of sperm. They are green plants Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. About 350,000 species of plants, defined as seed plants, bryophytes, ferns and fern allies, are estimated to exist currently. As of 2004, some 287,655 species had been believed to be the closest relatives of the green land plants. Linnaeus Carl Linnaeus (Latinized as Carolus Linnaeus, also known after his ennoblement as Carl von Linné , May 23 [O.S. May 13] 1707 – January 10, 1778) was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of established the genus (Chara) in 1753.

Contents

Description

The Charales, have large, macroscopic, thalli growing up to 120 cm long, they are branched, multicellular Multicellular organisms are organisms consisting of more than one cell, and having differentiated cells that perform specialized functions in the organism. Most life that can be seen with the naked eye is multicellular, as are all members of the kingdoms Plantae and Animalia, and use chlorophyll Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. Its name is derived from the Greek χλωρός and φύλλον (phyllon "leaf"). Chlorophyll absorbs light most strongly in the blue and red but poorly in the green portions of the electromagnetic spectrum, hence the green colour of chlorophyll-containing to photosynthesize. They grow in fresh water Freshwater refers to naturally occurring water on the surface such as bogs, ponds, lakes, rivers and streams, and underground in aquifers and underground rivers. Freshwater is characterized by having low concentrations of dissolved salts. The term specifically excludes seawater and brackish water. They may be called stoneworts,[1] because the plants can become encrusted in lime (calcium carbonate Calcium carbonate is a chemical compound with the chemical formula Ca ) after some time. The "stem" is actually a central stalk consisting of giant, multinucleated cells The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular . Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014. They are unique in having a whorl of small branchlets at each node in the stipe, this gives them a superficial resemblance to the genus Equisetum. In these whorls it is possible to see the phenomenon of cytoplasmic streaming Cytoplasmic streaming is the flowing of cytoplasm in eukaryotic cells. This occurs in both plant and animal cells. It creates cytoplasmic reorganization during cell reproduction. In some protists, such as amoeba, it provides the mechanism for cell locomotion. It aids in the delivery of nutrients, metabolites, and genetic information to all parts. In fact the streaming in Chara is the fastest recorded of any cell. Cytoplasmic streaming is caused by the microfilaments found inside the cell, as proven by the use of cytochalasin B to stop streaming.

There are about 400 species There are many definitions of what kind of unit a species is . A common definition is that of a group of organisms capable of interbreeding and producing fertile offspring, and separated from other such groups with which interbreeding does not (normally) happen. Other definitions may focus on similarity of DNA or morphology. Some species are world-wide, with 33 in Britain Great Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest in Europe. With a population of approximately 58.9 million people, it is the third most populated island on Earth. Ireland is to its west, and it is surrounded by over 1000 smaller islands and islets and Ireland Ireland (pronounced /ˈaɪrlənd/ , locally [ˈaɾlənd]; Irish: Éire, pronounced [ˈeːɾʲə] ( listen); Ulster Scots: Airlann, Latin: Hibernia) is the third-largest island in Europe, and the twentieth-largest island in the world. It lies to the north-west of continental Europe and is surrounded by hundreds of islands and islets. To the east of according to Groves and Bullock-Webster),[2][3] however (Stewart and Church (1992) reduce this to 21.[4]

Species

Submerse meadow of Chara spec. Limy crust on Chara spec. in a spring pond

British Isles

Ref: Stewart & Church (1992).[4]

Other regions

Distribution

This section requires expansion.

Ireland

Ecology

The Characeae are aquatic though some can survive in brackish or maritime habitats. They are to be found usually in still, clear, non-flowing, water attached by rhizoids. They can be pioneer colonizers or ephemerals. [9] They are usually found in low to medium nutrient-rich water and tend to disappear due to eutrophication.

Life history

The antheridia An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). It is present in the gametophyte phase of lower plants like mosses and ferns, and also in the primitive vascular psilotophytes. Many algae and some fungi, for example ascomycetes and water moulds, also have antheridia during their and oogonia An oogonium is an immature ovum. It is a female gametogonium. They are formed in large numbers by mitosis early in fetal life from primordial germ cells, which are present in the fetus between weeks 4 and 8 are protected by a layer of sterile cells The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular . Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 when mature; the oogonium is oblong in shape and consists of a single egg, while the spherical antheridium is packed with threadlike cells that produce spermatia. As a result, the Charales have the most complex structure of all green algae, if indeed they should be so labelled.

The possible ancestors of the land plants are also known as brittleworts or skunkweed. These curious labels arise from the fragility of their lime-encrusted stems, and from the foul odor these produce when stepped on.

Many botanists Botany, plant science, phytology, or plant biology is a branch of biology and is the scientific study of plant life and development. Botany covers a wide range of scientific disciplines that study plants, algae, and fungi including: structure, growth, reproduction, metabolism, development, diseases, chemical properties, and evolutionary propose that the stoneworts and their relatives be placed in a phylum In biology, a phylum [note 1] is a taxonomic rank above Kingdom and below Class. "Phylum" is equivalent to the botanical term division, division, sub-kingdom, or even kingdom by themselves, often named Charophyta The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are totally lacking. Flagellate cells in the form of sperm. Their classification Biological classification or scientific classification in biology, is a method by which biologists group and categorize organisms by biological type, such as genus or species. Biological classification is a form of scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis. Modern biological classification by taxonomists Taxonomy is the practice and science of classification. The word finds its roots in the Greek τάξις, taxis and νόμος, nomos ('law' or 'science'). Taxonomy uses taxonomic units, known as taxa (singular taxon) is currently undergoing much cladistic Cladistics is a form of biological systematics which classifies living organisms on the basis of shared ancestry. It can be distinguished from other taxonomic systems, such as phenetics, by its focus on evolutionary relationships; while other systems usually use morphological similarities to group similar species into genera, families and other scrutiny. Further DNA Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed and RNA Ribonucleic acid is a biologically important type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate. RNA is very similar to DNA, but differs in a few important structural details: in the cell, RNA is usually single-stranded, while DNA is usually double- analysis may prove the charophytes to be a crucial evolutionary In biology, evolution is the change in the genetic material of a population of organisms from one generation to the next. Though the changes produced in any one generation are small, differences accumulate with each generation and can, over time, cause substantial changes in the organisms. This process can culminate in the emergence of new species link in the phylogenetic tree A phylogenetic tree or evolutionary tree is a tree showing the evolutionary relationships among various biological species or other entities that are believed to have a common ancestor. In a phylogenetic tree, each node with descendants represents the most recent common ancestor of the descendants, and the edge lengths in some trees correspond to of life, the critical developmental step from the algae Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are toward the non-vascular Bryophytes are all embryophytes that are non-vascular: they have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. They neither have flowers nor produce seeds, reproducing via spores. The term bryophyte comes from Greek βρύον - bryon, "tree-moss, oyster-green" + φυτόν - fyton & and then vascular Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms. Scientific names for the group include Tracheophyta and Tracheobionta, but neither name is very widely used.[ land plants.

References

  1. ^ Kapraun DF (April 2007). "Nuclear DNA content estimates in green algal lineages: chlorophyta and streptophyta". Ann. Bot. 99 (4): 677–701. doi The Digital Object Identifier System is a managed system for persistent identification of content-related entities on digital networks. These entities may be content items (digital files, physical objects, abstract works), or any related entities in a content transaction (e.g. licenses, parties, etc.). "DOI" is sometimes used to mean the:10.1093/aob/mcl294. PMID 17272304. http://aob.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17272304.
  2. ^ Groves, J. and Bullock-Webster, G.R. 1920. The British Charophyta. Vol.1, Nitelleae. London, The Ray Society
  3. ^ Groves, J. and Bullock-Webster, G.R. 1924. The British Charophyta. Vol.2, Characeae.. London, The Ray Society
  4. ^ a b Stewart, N.F. and Church, J.M. 1992. Red Data Books of Britain and Ireland. The Joint Nature Conservation Committee, Peterborough. ISBN 1 873701 24 1
  5. ^ ITIS Standard Report Page: Chaetosphaeridiaceae
  6. ^ Algaebase :: Species Detail
  7. ^ a b c Morton, O. 1992 in Hackney, P. (Ed.) Stewart & Corry's Flora of the North-east of Ireland. Institute of Irish Studies and The Queen's University of Belfast ISBN 0 85389 446 9 (HB)
  8. ^ Guiry, M.D., John, D.M., Rindi, F. and McCarthy, T.K 2007. New Survey of Clare Island Volume:6: The Freshwater and Terrestial Algae. Royal Irish Academy. ISBN 978-1-904890-3-7
  9. ^ John, D.M., Whitton, B.A. and Brook, A.J. 2002. The Freshwater Algal Flora of the British Isles. Cambridge University Press, London. ISBN 0 521 77051 3

Further reading

Further links

Classification of Archaeplastida The Archaeplastida are a major line of eukaryotes, comprising the land plants, green and red algae, and a small group called the glaucophytes. All of these organisms have plastids surrounded by two membranes, suggesting they developed directly from endosymbiotic cyanobacteria. In all other groups, plastids are surrounded by three or four membranes, / Plantae sensu lato Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. About 350,000 species of plants, defined as seed plants, bryophytes, ferns and fern allies, are estimated to exist currently. As of 2004, some 287,655 species had been
Rhodophyta The red algae (or Rhodophyta, pronounced /roʊˈdɒfɨtə, ˌroʊdəˈfaɪtə/, from Greek: ῥόδον = rose + φυτόν (phyton) = plant, thus red plant) are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species of mostly multicellular, marine algae, including many notable seaweeds. Other Rhodophyceae · Bangiophyceae Bangiophyceae was a class of red algae; it has since been merged with the Floridophyceae to form the Rhodophyceae. The Bangiophyceae, as defined traditionally, are paraphyletic.. Their taxonomic identification has been difficult because of a lack of distinct morphological features, and the presumed morphological plasticity of the species · Florideophyceae Florideophyceae was a class of red algae. It is now merged with the Bangiaceae into the Rhodophyceae. They were once thought to be the only algae to bear pit connections, but these have since been found in the filamentous stage of the Bangiacae · Goniotrichales · Stylonematophyceae
Glaucocystophyceae The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater microscopic algae. Together with the red algae and Viridiplantae they form the Archaeplastida. However, the relationships between the red algae, green algae and glaucophytes are unclear, in large part due to limited study of the glaucophytes Glaucocystis · Cyanophora · Gloeochaete
Viridiplantae In some classification systems they have been treated as a kingdom, under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae/ Plantae sensu stricto
Chlorophyta Chlorophyta, a division of green algae, includes about 7000 species of mostly aquatic photosynthetic eukaryotic organisms. Like the land plants , green algae contain chlorophylls a and b, and store food as starch in their plastids. They are related to the Charophyta and Embryophyta (land plants), together making up the Viridiplantae/GA The green algae are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae). The green algae include unicellular and colonial flagellates, usually but not always Bryopsidophyceae In taxonomy, the Bryopsidophyceae are a class of green algae, in the division Chlorophyta · Chlorophyceae The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. For example the chlorophycean CW clade, and chlorophycean DO clade, are defined by the arrangement of their flagella. Members of the CW clade have flagella that are displaced in a "clockwise" direction eg · Pedinophyceae In taxonomy, the Pedinomonadaceae are a family of algae. They are small single-celled algae. Each cell has a single flagellum. It has been proposed to be either in the Mamiellales or the Ulvophyceae, but it has not been studied enough to confidently place it · Pleurastrophyceae In taxonomy, the Pleurastrophyceae are a class of green algae, in the division Chlorophyta. It was created by Mattox and Stewart in 1984, containing four genera. More recent classifications tend to split the group. On the one hand, Tetraselmis seems to be a sister to the so-called UTC clade , thus making it part of the (paraphyletic) · Prasinophyceae In taxonomy, Prasinophytes are a class of the Division Chlorophyta. These are primitive eukaryotic, marine green algae. Its best known genus is Ostreococcus , which is considered to be the smallest (ca. 0.95 μm) free-living eukaryote and which has been detected in marine samples around the world. Prasinophytes are thought to have low cellular · Trebouxiophyceae In taxonomy, the Trebouxiophyceae are a class of green algae, in the division Chlorophyta · Ulvophyceae The Ulvophyceae or Ulvophytes are class of green algae, distinguished mainly on the basis of ultrastructural morphology. The sea lettuce, Ulva, belongs here. Other well-known members include Ulothrix and Acetabularia. The Ulvophytes are diverse in their morphology and their habitat. Most are seaweeds such as those listed above. Others, such as
Streptophyta Streptophytina is formally a subdivision or subphylum which contains two classes: Charophyceae, containing the Charales order (Charophytes sensu stricto); and Embryophyceae, which contains the embryophytes (land plants, bryophytes, and vascular plants)
Charophyta The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are totally lacking. Flagellate cells in the form of sperm/GA The green algae are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae). The green algae include unicellular and colonial flagellates, usually but not always
Charophyceae Charophyceae is a taxon of green algae whose exact rank is the matter of some current debate. Some botanists recommend expanding the existing plant kingdom to include charophyceans and chlorophytes while others consider Charophyceae to be a class within either the divisions Chlorophyta, Streptophytina, or Streptophyta. Other systematists classify Charales
Coleochaetophyceae Coleochaetales
Zygnematophyceae Desmidiales · Zygnematales
Embryophyta/ Plantae sensu strictissimo
Bryophytes (non-vascular) Marchantiophyta · Anthocerotophyta · Bryophyta "Moss" · Horneophytopsida
Tracheophyta
Lycopodiophyta Isoetopsida (Isoetales, Selaginellales) · Lycopodiopsida (Lycopodiales)
Euphyllophyta Moniliformopses (Equisetopsida, Filicopsida, Psilotopsida) Spermatophyta: Gymnosperm (Pinophyta, Cycadophyta, Ginkgophyta, Gnetophyta) · Magnoliophyta
see also list of plant orders

Categories: Green algae | Plant taxonomy | Plant orders

 

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